Why NASCAR Single-Lug Wheels Proving to Be a Pain

Jackson Wheeler
8 Min Read

  • A growing safety issue is that NASCAR’s new wheel’s spokes are not able to contain the sparks flying from the air gun.
  • Team owner and driver Brad Keselowski says the old wheel had a “really deep dish to it and the sparks would tend to roll in that dish and stay inside the wheel assembly.”
  • One explanation is that the new air gun is heavier than the old one, and its nose weight is substantially greater as is its torque force.

NASCAR’s primary focus for more than a year has been making the current Cup car safer for the drivers, but during that time pit crew members have found themselves more susceptible to a new array of injuries due to the car’s new wheel.

Wrist, forearm, finger, and elbow injuries as well as tendinitis have become the norm due to the spokes on the wheel and the new, powerful impact wrench—air gun—needed to remove and reattach the single lug.

The wheel’s spokes are not able to contain the sparks flying from the air gun and RFK Racing co-owner Brad Keselowski believes the wheel’s design “lends itself to more fire risks.” With the single lug, Keselowski says the shower of sparks is different. He noted the old wheel had a “really deep dish to it and the sparks would tend to roll in that dish and stay inside the wheel assembly.”

“This car has a really shallow dish to the wheel, and it tends to shoot out the sparks … onto the ground,” Keselowski says.

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Sparks from a tire change hitting spilled fuel have led to several pit fires this season.

James Gilbert//Getty Images

In back-to-back races this year, the sparks have ignited racing fuel spilling from the car. At Darlington during the Cook Out Southern 500, the fuel spilled from Chris Buescher’s Ford burst into flames. A week later at Kansas Speedway, a fire erupted at the rear of William Byron’s Chevrolet. This time the rear tire changer’s uniform caught fire. He escaped injury because it was quickly extinguished by a firefighter assigned to the pit.


“We have implemented a new training policy at RFK for how to put fires out faster,” Keselowski says. “I don’t know if we’re ever gonna get away from having fires. It would take a significant design change to do so, but we can try to mitigate the damage and try to put them out as fast as possible.”

Meanwhile, pit crew members are dealing with injuries every week that increase as the season progresses because they don’t have time to heal.

Bill Heisel, director of OrthoCarolina Motorsports for 18 years, says the new wheel and powerful impact wrench—air gun—have created some serious injuries due to fingers being trapped between the back of the rim and the brake rotor.

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NASCAR’s one-lug wheel makes for quicker, but sometimes more fiery, pit stops.

Courtesy Bill Heisel

“In 2022, we had four instances, that I’m aware of, where tire carriers had their hands stuck behind the wheel,” Heisel says. “The jack didn’t drop but was about to drop, which could have resulted in a very bad situation. Fortunately, the communication between the jackman, the changer and the carrier have prevented such an accident from happening.”

That good communication between crew members kept one Team Penske tire carrier from losing a finger. Heisel says the tire carrier stuck his fingers through a wheel’s spokes, planted the wheel and before he could remove his fingers during a two-tire stop, the tire changer abruptly tightened the single lug. The crewman suffered an extensor tendon injury and the loss of skin, partial thickness on top of the tendon. Surgery wasn’t required, but he lost six weeks of work.

A crew member on another team broke a bone in one of his hands in late July when he reached in to grab the wheel, missed the hole and hit his hand on the wheel.

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A crew member works to put out a fire in the pits at New Hampshire earlier this season.

Jonathan Bachman//Getty Images

Heisel says the new air gun is heavier than the old one, and its nose weight is substantially greater as is its torque force. That combination taxes the forearm and the elbow and increases tendinitis on the wrist’s little finger side. Heisel says there are also tendinitis issues on the wrist’s thumb side from the firm grip required on the air gun. The tremendous torque forces through the air gun are twisting the ligaments at the back of the tire changers’ wrists. Heisel puts the weight of the tire and wheel assembly at about 50 pounds and the single-handed pull used in the sub-10-second pit stops is also causing wrist problems.

“We’re getting hand injuries from reaching into the spokes to pull,” Heisel says. “We’re getting ligament injuries between the metacarpal (palm bone) heads. We’re getting finger jams from reaching in quickly and hitting the spokes.”

The injuries are then aggravated throughout the season because they never have time to heal.

“On any given weekend (during the season) pit crew coaches may decide to ramp up practice for that team with a higher number of repetitions or a higher number of individual drills, which increases the cumulative trauma relative to the forearm, hand and wrist,” Heisel says.

Heisel estimates that in pre-season 5 to 7% of the sport’s tire changers suffer forearm, wrist, and hand injuries. That jumps to 15 to 20% in midseason and increases to 25 to 27% by year’s end. Cumulative trauma, the season’s length, and the fact many tire changers work in all three of NASCAR’s national touring series all contribute to the injury increase.

The new wheel isn’t solely responsible for the increase in injuries. The increase in road/street course races is also a contributing factor because all but one of the pit stops are executed backwards from those done on the ovals.

This year there were six road/street course races in the Cup Series. When coupled with eight road/street course races in Xfinity and two in truck, that’s a total of 16 road/street course races among the three series. The only one not requiring a backward pit stop is Charlotte Motor Speedway’s road course.

Heisel says back and shoulder injuries are prevalent on the road/street course pit stops that are backwards from the normal ones because crew members work a side of their body that’s not normally used.

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Jackson Wheeler is a skilled editor at Speedofdaily.com, specializing in automotive content. With a background in Journalism and Automotive Engineering, he combines his passion for cars with his writing expertise to deliver captivating articles. Jackson's deep knowledge of automotive technology and his racing experience make him a valuable asset to the team, providing readers with informative and engaging content.
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